Power sources provide electrical power that varies in accordance with conditions affecting the power source. Exemplary power sources include fuel cells, wind generators, photovoltaic modules and human powered generators. Power sources can output electricity with alternating current (AC) or direct current (DC). Wind generators, for example, can be configured to output single-phase, three-phase or DC power. The output of a wind generator varies with air speed and humidity. The output of a photovoltaic module converting solar energy varies with temperature, incidence angle and insolation level. Power output can also depend on the load connected to the power source. Power converters are used to convert the power output by the power source. As the functionality and complexity of these devices increases, exposure to extreme temperatures, solar radiation, wind and humidity increasingly reduces their reliability which increases costs.